At 15k miles of hard use the clutch in my M695 is showing slippage at WOT in the higher gears. Some of it might be due to my new light flywheel or the different brand/weight of (also correct) synthetic blend oil the shop used. Nonetheless, I need to start thinking about clutch pack replacement. The M695 uses the APTC "slipper" wet clutch and I'll likely stick with it as opposed to changing over to something else. I read the great threads on hub nuts and APTC workings.
The parts diagrams show that the M695 and S2R800 share the same clutch pack and springs. Search function showed that one person researched it and learned that the S2R800 used stronger springs? Can anyone shed some light on that? Barnett lists the same clutch pack and spring set part numbers for the M695, S2R800 and M696. The Barnett pack is about $200 and the Ducati pack is about $300.
What'll give me the most reliable and stout clutch? Ducati clutch pack and (presumably stronger than OE) Barnett springs?
Interested in hearing info and experiences with APTC clutch changes. [popcorn]
BK
Heavy duty spring for heavy duty power. It helps push the plates together to prevent them from slipping and burning out prematurely.
I had a bad experience with Barnett dry clutch packs, and im definitely not the only one. They suck for street use and are literally race application only. They lasted ~1,000 miles for me. From what people tell me, they last about 2 track days.
Ive heard good stuff for wet clutch though, but i never used it so dont take my word for it.
15K is not a lot of miles for a wet clutch. A light flywheel will not cause the clutch to slip, but oil is a possibility, particularly if this happened right after service. What oil did the shop use? What oil did you use before? Do you have sufficient play in the clutch lever? Insufficient free play will cause slip. You want 1-1.5 mm.
The parts manual shows the same part# for the clutch springs on both the 800 and 695, 797.1.022.1A.
Quote from: howie on December 20, 2009, 07:41:42 PM
15K is not a lot of miles for a wet clutch. A light flywheel will not cause the clutch to slip, but oil is a possibility, particularly if this happened right after service. What oil did the shop use? What oil did you use before? Do you have sufficient play in the clutch lever? Insufficient free play will cause slip. You want 1-1.5 mm.
The parts manual shows the same part# for the clutch springs on both the 800 and 695, 797.1.022.1A.
I use Mobil MX4T 10-40 full synthetic exclusively. The shop that did the recent work (nichols) used Golden Spectro 20-50 synthetic blend. Play at the lever seems good - CRG levers have been on for a couple years. My theory was that the recent engine work (light flywheel, valve adjust, trim adjust, cams degreed) boosted the power just enough to push things over the edge. Maybe the different oil contributed somehow. I do make extensive use of my clutch and the 15k is ALL in the twisties. Perhaps I should fill with my regular oil and see how it behaves?
BK
I notice clutch slip when I get my bike back from nichols also.
When I do my oil changes between the services that nichols does, I use the Platinum Spectro 20-50 FULL synthetic, and it doesn't seem to slip as much. I have an oil change due soon, so I'll report again after.
I really doubt your clutch slipping is due to extra power from the mods you mention. Also, the flywheel doesn't increase HP much...if at all...I checked. :-\
I'm thinking about getting a clutch from a non APCT bike. Maybe the Barnett 800sie kit.
Quote from: DarkStaR on December 20, 2009, 10:52:49 PM
I notice clutch slip when I get my bike back from nichols also.
When I do my oil changes between the services that nichols does, I use the Platinum Spectro 20-50 FULL synthetic, and it doesn't seem to slip as much. I have an oil change due soon, so I'll report again after.
I really doubt your clutch slipping is due to extra power from the mods you mention. Also, the flywheel doesn't increase HP much...if at all...I checked. :-\
I'm thinking about getting a clutch from a non APCT bike. Maybe the Barnett 800sie kit.
Interesting comment about your post-nichols service slippage. Maybe I can hold off on a new clutch pack! My intention was to get my usual oil back in there sooner rather than later anyway. Yeah, I know the light flywheel does not add power, but I was thinking more about internal engine dynamics and cylinder pulses helping to break the plates free and initiate slippage somehow with the super-light aluminum flywheel. Sounds far-fetched and I'm just inventing theoretical explanations!
What's the scoop on the 800sie kit?
BK
Hard to believe the Golden Spectro would cause slip, but it is cheaper than a new clutch pack. Have you thought about going back to Nichols and talking to them? They would want to know if the oil they are using is causing the problem. They also might know if the 800ei springs and/or clutch pack fit without issues.
I used Spectro oils in all my wet clutch 2 strokes and never experienced any slip.
At about 15K I noticed the same slippage you mentioned. I also have a lightened flywheel, FWIW. Different oil didn't really make a difference. I was thinking about going with heavier springs from a 750 or 800 (they'll fit), but wound up swapping the entire clutch for a non-APTC one from an 800ss. Engagement is awesome in comparison to the APTC.
The lightened flywheel has been called "the poor man's slipper clutch" because of how easy it makes rev-matching. The APTC is not a true slipper (more of a gimmick IMO). It saves the n00bs from some trouble if they ham-fist a down shift now and again. I have no reservations whatsoever about getting rid of it. I'm not the only one.
Clutch packs for APTC units are about $100 more than the standard clutch too. In the long run that's a lot of dough to shell out.
I bet your clutch isn't worn out at all BK, more probably its something like a bent push rod jamming inside its tunnel in the primary shaft, or some dirt's got in the works (this happened to my bike once and I got horrendous slippage) or as others have said… it's the hydraulic part of the system playing up, or you got wrong oil in it.
I recently dismantled the clutch on my S2R â€"1700 miles and its still in pristine nick with loads of wear left, it makes me think that the wet clutches might be very long lasting, I hope so too, because you have to buy the complete clutch and it aint cheap I belive.
Quote from: howie on December 21, 2009, 02:19:37 AM
Hard to believe the Golden Spectro would cause slip, but it is cheaper than a new clutch pack. Have you thought about going back to Nichols and talking to them? They would want to know if the oil they are using is causing the problem. They also might know if the 800ei springs and/or clutch pack fit without issues.
Yep, nichols is a great shop. I want to bring it up with them and get their input, but they're closed Sun/Mon. I was initially resignd to a new clutch pack, but after reading some of the comments here wrt typical long wet clutch life, maybe something else is going on.
BK
Thanks for the info, guys. [thumbsup]
Keep it coming!
BK
I put an inquiry into Barnett about their clutch springs for the APTC application. I got back two separate replies, one stating the springs are 10% stiffer, and another stating they are 5% stiffer and "pretty close to the stock spring tension." Springs are said to be locally manufactured under close supervision to tight tolerances, heat treated, shot peened, pre set to prevent sag. Compatible with OEM clutch pack. Maybe an easy way to get some additional clamping force? Brad Black thought that if regular ducati srings would fit, substituting just two out of the six would provide a substantial increase. Anyone BTDT?
BK
I'd be really interested if the 800 and 696 use the same springs. I have an '03 800 Dark and the clutch is heavey enough to take some getting used to. The biggest surprise for me on the 696 was squeezing the clutch, it felt light as a feather in comparison.
Scott
The '03 800 doesn't have the APTC.
Ah! Thanks, that was really puzzling. Especially since it didn't 'slip' on my last bad downshift.
Scott
FWIW, there's one on fleaBay that'll fit the OP's bike. Ends in about 2 hours at (Dec 21, 200918:38:16 PST)
At only $130, if I were the OP, I'd throw that one in place of the APTC and then wait until it starts slipping to buy a regular ole' wet clutch pack. Forget the APTC entirely.
http://cgi.ebay.com/ebaymotors/COMPLETE-CLUTCH-BASKET-DUCATI-750-SS-2000-00-01-99-900_W0QQcmdZViewItemQQhashZitem53de9c06fcQQitemZ360217052924QQptZMotorcyclesQ5fPartsQ5fAccessories (http://cgi.ebay.com/ebaymotors/COMPLETE-CLUTCH-BASKET-DUCATI-750-SS-2000-00-01-99-900_W0QQcmdZViewItemQQhashZitem53de9c06fcQQitemZ360217052924QQptZMotorcyclesQ5fPartsQ5fAccessories)
Quote from: DarkStaR on December 20, 2009, 10:52:49 PM
I notice clutch slip when I get my bike back from nichols also.
Just as another data point, I have never had clutch slip on my bike, and all my services (except a couple of oil changes at home) have been at nichols.
Found a little info on the '04 bikes with APTC:
http://www.sportrider.com/bikes/2004/146_04_ducati_aptc_clutch/index.html (http://www.sportrider.com/bikes/2004/146_04_ducati_aptc_clutch/index.html)
At least according to this the same springs were used on all bikes 620 and larger with 40% less lever effort from previous models like my '03.
Scott
Quote from: scott_araujo on December 22, 2009, 05:39:34 AM
Found a little info on the '04 bikes with APTC:
http://www.sportrider.com/bikes/2004/146_04_ducati_aptc_clutch/index.html (http://www.sportrider.com/bikes/2004/146_04_ducati_aptc_clutch/index.html)
At least according to this the same springs were used on all bikes 620 and larger with 40% less lever effort from previous models like my '03.
Scott
Thanks for posting the link - interesting read. Too bad they didn't go into greater mechanical detail. Scott, I think you meant to write that "the same springs were used on all bikes 620 and larger
WITH APTC." I spot-checked the part diagrams and as far as I can tell all ducatis with an APTC clutch (2004-2009) use the same clutch parts and springs. The other wet and dry cluches use different springs.
Some factoids from the article:
- normal ducati pressure plate compression force = 860N
- APTC pressure plate comporession force = 560N
- normal ducati clutch disc diameter = 150mm
- APTC clutch disc diameter = 140mm
- maximum clutch torque for both types = 9.98 Nm
And this interesting bit: "A unique technical solution has allowed the creation of a clutch in which the transmittable torque is, in part, independent from the pressure of the clutch springs." So maybe I'm barking up the wrong tree looking for stronger springs to minimize slippage?
BK
Quote from: BK_856er on December 22, 2009, 09:25:57 AM
"A unique technical solution has allowed the creation of a clutch in which the transmittable torque is, in part, independent from the pressure of the clutch springs." So maybe I'm barking up the wrong tree looking for stronger springs to minimize slippage?
BK
Heavier clutch springs will help a bit. Once you take apart the APTC, you'll see that there are some other little springs between the plate and the slipper hub. When "back-torque" is applied they work against the main springs to allow the clutch to slip. Heavier main springs will limit the amount of slippage.
BK, yes, with APTC. Thanks for the correction, that's what I meant. And yeah, interesting read but I wish there were some more technical details on exactly how it works too.
Scott
The grooves in the hub (that the steels engage) are cut at an angle, so under power, they clamp the plates tighter, and on overrun/closed throttle, they push the plates apart.
Same fundamental principle as a conventional slipper clutch, just a different execution.
Quote from: Speeddog on December 22, 2009, 11:01:20 AM
The grooves in the hub (that the steels engage) are cut at an angle, so under power, they clamp the plates tighter, and on overrun/closed throttle, they push the plates apart.
Same fundamental principle as a conventional slipper clutch, just a different execution.
That helps explain why the pressure plate spring tension is less important than on a standard clutch - forward torque should squeeze the plates together. I could not easily locate a good picture of the hub, but the following video (non ducati adige aptc) clearly shows the angled grooves. I kinda like the APTC setup.
APTC Video Assembly (http://www.youtube.com/watch?v=RgYIIcWW3K4#normal)
BK
Quote from: BK_856er on December 22, 2009, 12:00:34 PM
I kinda like the APTC setup.
I like it a lot better in theory than in practice.
BTW: I've got an extra APTC assembly lying around if anyone's interested.
Status update:
Clutch hydraulics. The shop bled the clutch as part of the service, but I did it again anyway and used their fluid brand - just a few tiny bubbles came out. Fluid action in the reservoir looked good. I also dropped the fluid level to the min line for the fun of it (more headspace). The piston free play was in spec when hot, but I backed out the CRG adjuster pin a little anyway. No real change on the 75-mile test run.
Motor oil. I changed back to my usual Mobil 1 MX4T 10W40 full synthetic. While I was draining the oil I noticed that both tank vent lines were severely kinked under the tank. Maybe some of my issue was fueling? Also caught what looks like the very beginning of a vertical cylinder cam seal leak. 50-mile test run today went well and I could not induce clutch slippage on hard WOT. I did notice that the clutch didn't seem to bite too hard on hard acceleration upshifts, so maybe things really are starting to wear, or that's just the nature of the (APTC) beast and I didn't pay attention to it before. I'll get some more miles in before I decide if I need to do anything else. For now I'm good to go.
So, like DarkStarR, my 15k mile APTC clutch does not pair well with the shop oil. I'm sure it's a fine oil and I'm not knocking it, but my clutch slips less with MX4T. As a reminder, the slippage I was experiencing was ONLY under relatively extreme conditions and not something that would be noticed in casual use.
I talked to the shop before I took the steps above and they were very interested in hearing about the oil outcome.
BK